Popular parks fill up early during hanami season. Junior salary men are sent out as early as 10 AM to reserve spots. Most juniors enjoy the job. It's a good break from the pressures of the office. They sit in the park watching the girls walk by all day.
Sometimes a more senior salary man grabs this choice assignment.
These days, mobile devices mean that many juniors are expected to work while reserving a spot.
Around 6 PM the first coworkers start to join — the party begins. By 10 PM everyone is enjoying the party.